When a “Routine” Surgery Carries Hidden Risks Understanding Metal-on-Metal Hip Replacements Total hip replacement is now one of the most common orthopedic surgeries performed in the United States. Roughly 400,000 procedures are done annually. For many people with severe joint degeneration, hip replacement can restore mobility and dramatically improve quality of life. When successful, modern implants may last 20 years or more. But not all hip implants are created equal — and certain designs have raised significant safety concerns. The Metal-on-Metal (MOM) Issue The hip is a ball-and-socket joint. In a total replacement, both components are substituted with artificial materials. These materials may include: Ceramic Plastic (polyethylene) Metal In “metal-on-metal” (MOM) implants, both the ball and socket are made of metal alloys. While these designs were initially promoted for durability, post-market surveillance and patient reports revealed a seriou…